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Commit 6138a0b0 by huangdarwin Committed by Ian Baker
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FrameProcessor: Improve PresentationFrameProcessor javadocs. 

PiperOrigin-RevId: 442835160
parent 7e76f773
Inline Side-by-side
Showing with 104 additions and 58 deletions
library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/PresentationFrameProcessorPixelTest.java
......@@ -182,7 +182,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_scaleToFit_narrow";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(1f, PresentationFrameProcessor.SCALE_TO_FIT)
.setAspectRatio(1f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......@@ -211,7 +211,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_scaleToFit_wide";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(2f, PresentationFrameProcessor.SCALE_TO_FIT)
.setAspectRatio(2f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......@@ -240,7 +240,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_scaleToFitWithCrop_narrow";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(1f, PresentationFrameProcessor.SCALE_TO_FIT_WITH_CROP)
.setAspectRatio(1f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT_WITH_CROP)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......@@ -269,7 +269,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_scaleToFitWithCrop_wide";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(2f, PresentationFrameProcessor.SCALE_TO_FIT_WITH_CROP)
.setAspectRatio(2f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT_WITH_CROP)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......@@ -298,7 +298,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_stretchToFit_narrow";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(1f, PresentationFrameProcessor.STRETCH_TO_FIT)
.setAspectRatio(1f, PresentationFrameProcessor.LAYOUT_STRETCH_TO_FIT)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......@@ -327,7 +327,7 @@ public final class PresentationFrameProcessorPixelTest {
String testId = "drawFrame_changeAspectRatio_stretchToFit_wide";
presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(2f, PresentationFrameProcessor.STRETCH_TO_FIT)
.setAspectRatio(2f, PresentationFrameProcessor.LAYOUT_STRETCH_TO_FIT)
.build();
presentationFrameProcessor.initialize(
getApplicationContext(), inputTexId, inputWidth, inputHeight);
......
library/transformer/src/main/java/com/google/android/exoplayer2/transformer/AdvancedFrameProcessor.java
......@@ -27,11 +27,14 @@ import java.io.IOException;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
/**
* Applies a transformation matrix in the vertex shader.
* Applies a transformation matrix in the vertex shader, and copies input pixels into an output
* frame based on their locations after applying this matrix.
*
* <p>Operations are done on normalized device coordinates (-1 to 1 on x and y axes). No automatic
* adjustments (like done in {@link ScaleToFitFrameProcessor}) are applied on the transformation.
* Width and height are not modified. The background color will default to black.
* Width and height are not modified.
*
* <p>The background color of the output frame will be black.
*/
@SuppressWarnings("FunctionalInterfaceClash") // b/228192298
public final class AdvancedFrameProcessor implements GlFrameProcessor {
......
library/transformer/src/main/java/com/google/android/exoplayer2/transformer/GlFrameProcessor.java
......@@ -20,7 +20,8 @@ import android.util.Size;
import java.io.IOException;
/**
* Manages a GLSL shader program for processing a frame.
* Manages a GLSL shader program for processing a frame. Implementations generally copy input pixels
* into an output frame, with changes to pixels specific to the implementation.
*
* <p>Methods must be called in the following order:
*
......
library/transformer/src/main/java/com/google/android/exoplayer2/transformer/PresentationFrameProcessor.java
......@@ -38,33 +38,72 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
import org.checkerframework.checker.nullness.qual.RequiresNonNull;
/**
* Controls how a frame is viewed, by cropping, changing aspect ratio, or changing resolution.
* Controls how a frame is presented, by copying input pixels into an output frame, with options to
* set the output resolution, crop the input, and choose how to map the input pixels onto the output
* frame geometry (for example, by stretching the input frame to match the specified output frame,
* or fitting the input frame using letterboxing).
*
* <p>Cropping or aspect ratio is applied before setting resolution.
*
* <p>The background color of the output frame will be black.
*/
public final class PresentationFrameProcessor implements GlFrameProcessor {
/**
* Strategies for how to apply the presented frame. One of {@link #SCALE_TO_FIT}, {@link
* #SCALE_TO_FIT_WITH_CROP}, or {@link #STRETCH_TO_FIT}.
* Strategies controlling the layout of input pixels in the output frame.
*
* <p>One of {@link #LAYOUT_SCALE_TO_FIT}, {@link #LAYOUT_SCALE_TO_FIT_WITH_CROP}, or {@link
* #LAYOUT_STRETCH_TO_FIT}.
*
* <p>May scale either width or height, leaving the other output dimension equal to its input,
* unless {@link Builder#setResolution(int)} rescales width and height.
*/
@Documented
@Retention(SOURCE)
@Target(TYPE_USE)
@IntDef({SCALE_TO_FIT, SCALE_TO_FIT_WITH_CROP, STRETCH_TO_FIT})
public @interface PresentationStrategy {}
@IntDef({LAYOUT_SCALE_TO_FIT, LAYOUT_SCALE_TO_FIT_WITH_CROP, LAYOUT_STRETCH_TO_FIT})
public @interface Layout {}
/**
* Empty pixels added above and below the input frame (for letterboxing), or to the left and right
* of the input frame (for pillarboxing), until the desired aspect ratio is achieved. All input
* frame pixels will be within the output frame.
*
* <p>When applying:
*
* <ul>
* <li>letterboxing, the output width will default to the input width, and the output height
* will be scaled appropriately.
* <li>pillarboxing, the output height will default to the input height, and the output width
* will be scaled appropriately.
* </ul>
*/
public static final int LAYOUT_SCALE_TO_FIT = 0;
/**
* Pixels cropped from the input frame, until the desired aspect ratio is achieved. Pixels may be
* cropped either from the bottom and top, or from the left and right sides, of the input frame.
*
* <p>When cropping from the:
*
* <ul>
* <li>bottom and top, the output width will default to the input width, and the output height
* will be scaled appropriately.
* <li>left and right, the output height will default to the input height, and the output width
* will be scaled appropriately.
* </ul>
*/
public static final int SCALE_TO_FIT = 0;
public static final int LAYOUT_SCALE_TO_FIT_WITH_CROP = 1;
/**
* Pixels cropped from the input frame, until the desired aspect ratio is achieved. Pixels will be
* cropped either from the top and bottom, or from the left and right sides, of the input frame.
* Frame stretched larger on the x or y axes to fit the desired aspect ratio.
*
* <p>When stretching to a:
*
* <ul>
* <li>taller aspect ratio, the output width will default to the input width, and the output
* height will be scaled appropriately.
* <li>narrower aspect ratio, the output height will default to the input height, and the output
* width will be scaled appropriately.
* </ul>
*/
public static final int SCALE_TO_FIT_WITH_CROP = 1;
/** Frame stretched larger on the x or y axes to fit the desired aspect ratio. */
public static final int STRETCH_TO_FIT = 2;
public static final int LAYOUT_STRETCH_TO_FIT = 2;
/** A builder for {@link PresentationFrameProcessor} instances. */
public static final class Builder {
......@@ -76,7 +115,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
private float cropBottom;
private float cropTop;
private float aspectRatio;
private @PresentationStrategy int presentationStrategy;
private @Layout int layout;
/** Creates a builder with default values. */
public Builder() {
......@@ -91,7 +130,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
/**
* Sets the output resolution using the output height.
*
* <p>The default value {@link C#LENGTH_UNSET} corresponds to using the same height as the
* <p>The default value, {@link C#LENGTH_UNSET}, corresponds to using the same height as the
* input. Output width of the displayed frame will scale to preserve the frame's aspect ratio
* after other transformations.
*
......@@ -111,10 +150,12 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
* frame corresponds to the square ranging from -1 to 1 on the x and y axes.
*
* <p>{@code left} and {@code bottom} default to -1, and {@code right} and {@code top} default
* to 1. To crop to a smaller subset of the input frame, use values between -1 and 1. To crop to
* a larger frame, use values below -1 and above 1.
* to 1, which corresponds to not applying any crop. To crop to a smaller subset of the input
* frame, use values between -1 and 1. To crop to a larger frame, use values below -1 and above
* 1.
*
* <p>Width and height values set may be rescaled by {@link #setResolution(int)}.
* <p>Width and height values set may be rescaled by {@link #setResolution(int)}, which is
* applied after cropping changes.
*
* <p>Only one of {@code setCrop} or {@link #setAspectRatio(float, int)} can be called for one
* {@link PresentationFrameProcessor}.
......@@ -142,43 +183,40 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
}
/**
* Resize a frame's width or height to conform to an {@code aspectRatio}, given a {@link
* PresentationStrategy}, and leaving input pixels unchanged.
* Sets the aspect ratio (width/height ratio) for the output frame.
*
* <p>Resizes a frame's width or height to conform to an {@code aspectRatio}, given a {@link
* Layout}. {@code aspectRatio} defaults to {@link C#LENGTH_UNSET}, which corresponds to the
* same aspect ratio as the input frame. {@code layout} defaults to {@link #LAYOUT_SCALE_TO_FIT}
*
* <p>Width and height values set here may be rescaled by {@link #setResolution(int)}.
* <p>Width and height values set may be rescaled by {@link #setResolution(int)}, which is
* applied after aspect ratio changes.
*
* <p>Only one of {@link #setCrop(float, float, float, float)} or {@code setAspectRatio} can be
* called for one {@link PresentationFrameProcessor}.
*
* @param aspectRatio The aspect ratio of the output frame, defined as width/height. Must be
* @param aspectRatio The aspect ratio (width/height ratio) of the output frame. Must be
* positive.
* @return This builder.
*/
public Builder setAspectRatio(
float aspectRatio, @PresentationStrategy int presentationStrategy) {
public Builder setAspectRatio(float aspectRatio, @Layout int layout) {
checkArgument(aspectRatio > 0, "aspect ratio " + aspectRatio + " must be positive");
checkArgument(
presentationStrategy == SCALE_TO_FIT
|| presentationStrategy == SCALE_TO_FIT_WITH_CROP
|| presentationStrategy == STRETCH_TO_FIT,
"invalid presentationStrategy " + presentationStrategy);
layout == LAYOUT_SCALE_TO_FIT
|| layout == LAYOUT_SCALE_TO_FIT_WITH_CROP
|| layout == LAYOUT_STRETCH_TO_FIT,
"invalid layout " + layout);
checkState(
cropLeft == -1f && cropRight == 1f && cropBottom == -1f && cropTop == 1f,
"setAspectRatio and setCrop cannot be called in the same instance");
this.aspectRatio = aspectRatio;
this.presentationStrategy = presentationStrategy;
this.layout = layout;
return this;
}
public PresentationFrameProcessor build() {
return new PresentationFrameProcessor(
heightPixels,
cropLeft,
cropRight,
cropBottom,
cropTop,
aspectRatio,
presentationStrategy);
heightPixels, cropLeft, cropRight, cropBottom, cropTop, aspectRatio, layout);
}
}
......@@ -192,7 +230,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
private final float cropBottom;
private final float cropTop;
private final float requestedAspectRatio;
private final @PresentationStrategy int presentationStrategy;
private final @Layout int layout;
private int outputRotationDegrees;
private int outputWidth;
......@@ -208,14 +246,14 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
float cropBottom,
float cropTop,
float requestedAspectRatio,
@PresentationStrategy int presentationStrategy) {
@Layout int layout) {
this.requestedHeightPixels = requestedHeightPixels;
this.cropLeft = cropLeft;
this.cropRight = cropRight;
this.cropBottom = cropBottom;
this.cropTop = cropTop;
this.requestedAspectRatio = requestedAspectRatio;
this.presentationStrategy = presentationStrategy;
this.layout = layout;
outputWidth = C.LENGTH_UNSET;
outputHeight = C.LENGTH_UNSET;
......@@ -324,7 +362,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
@RequiresNonNull("transformationMatrix")
private void applyAspectRatio() {
float inputAspectRatio = (float) outputWidth / outputHeight;
if (presentationStrategy == SCALE_TO_FIT) {
if (layout == LAYOUT_SCALE_TO_FIT) {
if (requestedAspectRatio > inputAspectRatio) {
transformationMatrix.setScale(inputAspectRatio / requestedAspectRatio, 1f);
outputWidth = Math.round(outputHeight * requestedAspectRatio);
......@@ -332,7 +370,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
transformationMatrix.setScale(1f, requestedAspectRatio / inputAspectRatio);
outputHeight = Math.round(outputWidth / requestedAspectRatio);
}
} else if (presentationStrategy == SCALE_TO_FIT_WITH_CROP) {
} else if (layout == LAYOUT_SCALE_TO_FIT_WITH_CROP) {
if (requestedAspectRatio > inputAspectRatio) {
transformationMatrix.setScale(1f, requestedAspectRatio / inputAspectRatio);
outputHeight = Math.round(outputWidth / requestedAspectRatio);
......@@ -340,7 +378,7 @@ public final class PresentationFrameProcessor implements GlFrameProcessor {
transformationMatrix.setScale(inputAspectRatio / requestedAspectRatio, 1f);
outputWidth = Math.round(outputHeight * requestedAspectRatio);
}
} else if (presentationStrategy == STRETCH_TO_FIT) {
} else if (layout == LAYOUT_STRETCH_TO_FIT) {
if (requestedAspectRatio > inputAspectRatio) {
outputWidth = Math.round(outputHeight * requestedAspectRatio);
} else {
......
library/transformer/src/main/java/com/google/android/exoplayer2/transformer/ScaleToFitFrameProcessor.java
......@@ -30,9 +30,12 @@ import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
/**
* Applies a simple rotation and/or scale in the vertex shader. All input frames' pixels will be
* preserved, potentially changing the width and height of the frame by scaling dimensions to fit.
* The background color will default to black.
* Applies a simple rotation and/or scale in the vertex shader.
*
* <p>All input frames' pixels will be preserved and copied into an output frame, potentially
* changing the width and height of the frame by scaling dimensions to fit.
*
* <p>The background color of the output frame will be black.
*/
public final class ScaleToFitFrameProcessor implements GlFrameProcessor {
......
library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformationRequest.java
......@@ -100,7 +100,8 @@ public final class TransformationRequest {
* Sets the x and y axis scaling factors to apply to each frame's width and height, stretching
* the video along these axes appropriately.
*
* <p>The values default to 1, which corresponds to not scaling along both axes.
* <p>The default value for {@code scaleX} and {@code scaleY}, 1, corresponds to not scaling
* along the x and y axes, respectively.
*
* @param scaleX The multiplier by which the frame will scale horizontally, along the x-axis.
* @param scaleY The multiplier by which the frame will scale vertically, along the y-axis.
......@@ -137,7 +138,7 @@ public final class TransformationRequest {
*
* <p>For example, a 1920x1440 video can be scaled to 640x480 by calling setResolution(480).
*
* <p>The default value {@link C#LENGTH_UNSET} leaves the width and height unchanged unless
* <p>The default value, {@link C#LENGTH_UNSET}, leaves the width and height unchanged unless
* {@linkplain #setScale(float,float) scaling} or @linkplain #setRotationDegrees(float)
* rotation} are requested.
*
......
library/transformer/src/test/java/com/google/android/exoplayer2/transformer/PresentationFrameProcessorTest.java
......@@ -175,7 +175,7 @@ public final class PresentationFrameProcessorTest {
float aspectRatio = 2f;
PresentationFrameProcessor presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(aspectRatio, PresentationFrameProcessor.SCALE_TO_FIT)
.setAspectRatio(aspectRatio, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT)
.build();
presentationFrameProcessor.configureOutputSizeAndTransformationMatrix(inputWidth, inputHeight);
......@@ -194,7 +194,7 @@ public final class PresentationFrameProcessorTest {
int requestedHeight = 100;
PresentationFrameProcessor presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(aspectRatio, PresentationFrameProcessor.SCALE_TO_FIT)
.setAspectRatio(aspectRatio, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT)
.setResolution(requestedHeight)
.build();
......@@ -210,7 +210,7 @@ public final class PresentationFrameProcessorTest {
public void getOutputSize_setAspectRatioAndCrop_throwsIllegalStateException() {
PresentationFrameProcessor.Builder presentationFrameProcessor =
new PresentationFrameProcessor.Builder()
.setAspectRatio(/* aspectRatio= */ 2f, PresentationFrameProcessor.SCALE_TO_FIT);
.setAspectRatio(/* aspectRatio= */ 2f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT);
assertThrows(
IllegalStateException.class,
......@@ -229,7 +229,7 @@ public final class PresentationFrameProcessorTest {
IllegalStateException.class,
() ->
presentationFrameProcessor.setAspectRatio(
/* aspectRatio= */ 2f, PresentationFrameProcessor.SCALE_TO_FIT));
/* aspectRatio= */ 2f, PresentationFrameProcessor.LAYOUT_SCALE_TO_FIT));
}
@Test
......
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